Just as an online petition to re-legalize unlocking has surpassed 100,000 signatures in the United States, meaning the White House must issue a response, Apple’s phone-locking is under heavy fire in Hong Kong, where a local carrier alarmed watchdogs that it lost big money over the policy. Having discovered that the iPhone 5 wasn’t functioning on its fourth-generation network, Hong Kong Telecom (HKT), a unit of telecommunications operator PCCW Ltd., filed court documents and is now seeking to contest the practice…

According to The Wall Street Journal, a complaint HKT filed with regulators claims it lost “hundreds of millions of Hong Kong dollars” because the iPhone 5 doesn’t work on its 4G network.

Interestingly enough, before the iPhone 5 launched most iPhones sold in Hong Kong were unlocked models that could access 2G or 3G network.

HKT argues Apple could easily disable the phone-lock via a simple settings change, if it wanted to. The complaint accuses the iPhone maker of hurting consumers who would only later on find out that “they were having their choice of mobile service provider dictated (or limited) by Apple.”

The Journal writes:

On Sept. 28, shortly after PCCW discovered that the iPhone 5 wasn’t functioning on its fourth-generation network, its unit, Hong Kong Telecommunications, filed a complaint with the city’s telecommunications regulator. That effort hasn’t yielded any success, prompting the operator to turn to the city’s legal system instead.

HKT is now seeking a review of Apple’s iPhone locking practices. Should the court grant a judicial review, “it would open the way to the city’s first legal challenge of Apple’s locking practices” in Hong Kong’s highly competitive market, the Journal writes.

Apple’s retail store at Hong Kong’s Hysan Place.

Unlocked iPhones are offered in a lot of markets, but many wireless carriers are happy with network locks preventing contractual customers from jumping ship. The DCMA exemption that made unlocking legal expired on January 26, meaning unlocking your iPhone is currently illegal in the United States.

Should the Librarian of Congress fail to rescind the DMCA exemption decision on unlock, the petition seeks to champion a bill or some other form of legislation making unlocking permanently legal.